Indicia reading terminals are available in multiple varieties. Well-known among the varieties is the gun style terminal as commonly seen at retail store checkout counters. Other terminals are also available that provide enhanced functions, have keyboards, and displays, and include advanced networking communication capabilities. Many indicia reading terminals also have triggers for activating decoding attempts.
Typically indicia reading terminals are implemented to decode decodable indicia that are readily visible. Advances in security and similar precautionary protocols tend, however, to utilize decodable indicia that are only visible in the presences of non-visible light such as UV light. These non-visible indicia are often printed with materials such as ink so that to the naked eye the indicia do not appear to be present on the document, package, or device.
Known devices used to decode non-visible indicia comprise UV fluorescent illuminating devices which emit UV illumination. Short wavelength diodes have been used, for example, to emit light in the deep blue to near UV region of the spectrum, and can be used to produce illumination compatible with the non-visible indicia. These devices are somewhat limited in their application, however, because although they can illuminate the non-visible indicia, actual decoding of the indicia is particularly sensitive to the position, orientation, and other physical alignment between the devices and the illuminated non-visible indicia.
There is a need, therefore, for an indicia reading terminal that can decode both visible and non-visible decodable indicia, and in one example there is a need for such terminal that can decode these types of indicia without substantial reduction in the depth of field of the terminal.